Welding rotator TR

The Anti-Drift Roll has two synchronized "Steerable Wheels." Each axle is connected to a gearbox, which is driven by an AC servo motor. As each axle is rotated, the relationship between the axis of rotation of each wheel and the axis of rotation of the vessel changes. This change creates a thrust load on the vessel to counter vessel lateral movement. The amount and direction of axle rotation is commanded by the Anti-Drift Control. Each axle is fitted with a "Neutral Position Indicator" (arrow) to provide a reference to the plane of rotation for the wheel. During initial set-up, the axles are rotated to visually align each arrow to the contact point between the wheels and the vessel, ensuring that the centerline of rotation of each wheel is nearly in the same plane as the centerline of the vessel and that maximum "steering" can be accomplished with +/­ 90˚ rotation of each axle. During operation, an electrical signal from the Drift Sensor (transducer or laser that tracks the vessel) is fed to the Anti-Drift Control. The control commands the idler axles to rotate in proportion to the error signal and in the correct direction to counter the vessel drift. The system maintains a vessels girth joint within +/-3 mm maximum longitudinal movement. A programmable over-travel distance produces an audible alarm and delayed rotation stop in the event the vessel drift exceeds this value.